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This work investigates the effect of a multifunctional diesel fuel additive package used with RapeSeed Oil (RSO) as a fuel in a DI heavy duty diesel engine. The effects on fuel injectors’ cleanliness were assessed. The aim was to maintain combustion performance and preventing the deterioration of exhaust emissions associated with injector deposit build up. Two scenarios were investigated: the effect of deposit clean-up by a high dose of the additive package; and the effect of deposit prevention using a moderate dose of the additive package. Engine combustion performance and emissions were compared for each case against use of RSO without any additive. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, fitted with an oxidation catalyst and meeting the Euro II emissions limits. The tests were conducted under steady state conditions of 23kW and 47kW power output at an engine speed of 1500 rpm.

A Gas to liquid (GTL) fuel was investigated for its combustion and emission performance in an IVECO EURO5 DI diesel engine with a DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particle Filter) installed. The composition of the GTL fuel was analyzed by GC-MS (gas chromatography-mass spectrometry) and showed the carbon distribution of 8-20. Selected physical properties such as density and distillation were measured. The GTL fuel was blended with standard fossil diesel fuel by ratios of diesel/GTL: 100/0, 70/30, 50/50, 30/70 and 0/100. The engine was equipped with a pressure transducer and crank angle encoder in one of its cylinders. The properties of ignition delay and maximum in-cylinder pressure were studied as a function of fraction of the GTL fuel. Particle emissions were measured using DMS500 particle size instrument at both upstream (engine out) and downstream of the DPF (DPF out) for particle number concentrations and size distribution from 5 nm to 1000 nm.

A rapeseed methyl ester biodiesel RMEB100 was tested on a heavy duty DI diesel engine under steady state conditions. The combustion performance and exhaust emissions were measured and compared to a standard petroleum derived diesel fuel. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Phaser Engine, with emission compliance of EURO 2, fitted with an oxidation catalyst. The exhaust samples were taken both upstream and downstream of the catalyst. Particulates were collected and analysed for VOF, carbon and ash. A MEXA7100 gas analysis system was used for legislated gas analysis such as CO, CO2, NOx and total hydrocarbons. A FTIR analysis system was deployed for gaseous hydrocarbon speciation, which is capable of speciating up to 65 species. The results showed a significant reduction in total particulate mass, particulate VOF, CO, THC and aldehydes when using RMEB100.

Rape oil, as used in fresh cooking oil (FCO), and the methyl ester derived from waste cooking oil (WCOB100) were tested as 100% biofuels (B100) on a heavy duty DI diesel engine under steady state conditions. The exhaust emissions were measured and compared to those for conventional low sulphur (<50ppm) diesel fuel. The engine used was a 6 cylinder, turbocharged, intercooled Perkins Euro2 Phaser Engine, fitted with an oxidation catalyst. The engine out gaseous emissions results for WCOB100 showed a large decrease in CO and HC emissions, but a small increase in NOx emissions compared to diesel. However, for FCO the CO and HC increased relative to WCOB100 and CO was higher than for diesel, indicating deterioration in fuel/air mixing. The particulate matter (PM) emissions for WCOB100 were similar to those for diesel at the 23kw condition, but greatly reduced at 47kw. The FCO produced higher engine out PM at both power conditions due to a higher volatile organic fraction (VOF).

Aldehydes and other Volatile Organic compounds (VOC) are assessed under cold start and steady state conditions using a Perkins Phaser 6 litre diesel engine. A comparison is made between petroleum diesel fuel (PD), 100% biodiesel (WME) and 100% rapeseed oil (RSO). A Temet FTIR was used to determine aldehydes including formaldehyde, acetaldehyde and acrolein. The diesel engine was cold started at room temperature using a step start up procedure that kept the power output constant at two steady state conditions: 23kW and 47kW. Very little difference was observed between petroleum diesel and biodiesel aldehyde emissions at either steady state conditions or during cold start. There was, however, an increase in aldehydes at steady state for rapeseed oil, particularly at low load, but only for from ∼10ppm to 25 ppm for formaldehyde (i.e. 0.12g/kWh to 0.37g/kWh). During cold start conditions, the emissions were significantly higher for rapeseed oil than for petroleum diesel.

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infrared heater, to remove water and light diesel fractions in the oil. The impact of this oil recycler with 1 micron fine bypass filter on oil quality was investigated over a 72 hour oil age. Comparisons tests were undertaken without and with the recycler on a Euro 2 Perkins Phaser 180Ti 6 cylinder 6 litre turbo-charged inter-cooled DI diesel engine. The tests were carried out at 2000rpm and 100kW with 473 Nm load. A stop start test cycle was used with a cold start each time and a typical test period of 2 hours. The results showed that the oil quality in this low emission engine test was extremely good. The on line recycler achieved improvements in the oil quality. With the recycler, the carbon accumulation rate in the oil was reduced by 78%. The carbon removal rate by the recycler was 0.40 g/hr. The wear metals in the oil were significantly reduced.

This work is part of a larger programme to investigate the storage at low power conditions and release at high power conditions in real diesel engine exhaust systems. The initial particle storage in the oxidation catalyst, followed by a release of particles a few minutes later, is explored, and the associated particle size distribution changes determined. A Ford 1.8L IDI Diesel Engine, Turbocharged and Intercooled (TCIC), and equipped with Exhaust Gas Recirculation (EGR), was used under high speed and high power conditions, both during cold start. The commercial close-coupled diesel oxidation catalyst had an associated hydrocarbon adsorber for cold start hydrocarbon control. The tests were carried out using a step cold start to a fixed low power output, typical of city driving. The ELPI particle size analyser was used together with constant temperature gravimetric filter based mass samples upstream and downstream of the catalyst.

A method of cleaning lubricating oil on line was investigated using a fine 1μm bypass particulate filter followed by a 150°C infra-red heater, to remove water and light diesel fractions in the oil. The impact of this oil recycler on diesel particulate and gaseous emissions was investigated over a 72 hour oil age. Comparison tests were undertaken without and with the recycler on a Euro 2 Perkins Phaser 180Ti, 6-cylinder, 6-litre, turbo-charged inter-cooled DI diesel engine fitted with an oxidation catalyst. Emissions were sampled from both upstream and downstream of the catalyst about every 10 hours. The tests were carried out at 2000rpm and 100kW with 473 Nm load. A stop start test cycle was used with a cold start each time and a typical test period of 2 hours. The results showed that this engine had extremely low particulate emissions and was well inside the Euro 2 emissions limits.

An oxidation catalyst was fitted on a DI diesel engine for an experimental study involving an oxidation catalyst and the use of superheated steam for fumigating the intake air. Results are compared with that of the influence of low level of fumigation of the intake air with superheated diesel fuel. Exhaust emissions of NOx, CO, UHC, TPM, SOF and Carbon were measured and quantified on upstream and downstream of a low light off temperature (250 °C) oxidation catalyst. The technique used an electric vaporizer for producing superheated steam and prevaporised superheated diesel fumes at 350 °C, respectively. A low emissions version of Perkins 4-236 engine with squish lip piston was run both with and without fumigation at two speeds 1200 rpm and 2200 rpm. Roughly covering both city and highway running conditions.

Results showed the influence of the oxidation catalyst on exhaust emissions from a DI diesel engine due to the partial premixing, fumigation of the intake air with diesel fuel. Exhaust emissions of NOx, CO, UHC, TPM, SOF and Carbon were measured and quantified on upstream and downstream of a low light off temperature (250 °C) oxidation catalyst. Two methods of diesel fumigation of the intake air with fuel were used. The difference between these two methods was the degree of premixing of diesel fuel with the intake air. The first technique used a high-pressure fine diesel spray onto a glow plug and the second technique used an electric vaporizer for prevaporised superheated diesel fumes at 350 °C. A low emissions version of Perkins 4-236 engine with squish lip piston was run both with and without fumigation at two speeds 1200 rpm and 2200 rpm. Roughly covering both city and highway running conditions.

Results of an experimental study of a DI Diesel engine are presented, which show the influence of partial premixing fumigation of the intake air with diesel fuel on the exhaust emissions and the engine performance parameters. Exhaust emissions of NOx, CO, UHC, TPM, SOF and Carbon were measured and quantified. Engine performance parameters include the event of the start of combustion and fuel consumption besides other parameters, which were published elsewhere. The study also showed that during a “normal operation” of a DI diesel engine, no emissions trade-off exists between NOx and TPM. Rather these emissions need separate technological measures for their specific control. Two methods of diesel fumigation were used. The difference between these two methods was the degree of premixing of diesel fuel with the intake air.

Reduction of NOx was achieved in an experimental study in a DI Diesel engine. Results are presented, which show the comparison of the influence of partial fumigation of the intake air with superheated diesel fuel vapour and that of steam on the exhaust emissions and the engine performance parameters. Exhaust emissions of NOx, CO, UHC, TPM, SOF and Carbon were measured and quantified. The technique used for fumigating the intake air with fuel and steam consisted of an electric vaporizer for producing perfectly prevaporised superheated diesel fumes and steam at 350°C. A low emissions version of Perkins 4-236 engine with squish lip piston was run with the fumigation of the intake air with superheated fuel vapour and that of steam at two speeds 1200 rpm and 2200 rpm, roughly covering both city and highway running conditions.

Pure rape seed oil (RSO), as coded BO100 (BO: Bio-Oil) to distinguish from biodiesel was investigated for a range of intake oxygen levels from 21 to 24%. RSO can have deposit problems in both the fuel injector and piston crown and elevated intake oxygen levels potentially could control these by promoting their oxidation. Increased intake oxygen elevates the peak temperature and this promotes the oxidation of soot and volatile organic compounds. The effect of this on particle mass and on the particle size distribution was investigated using a 6-cylinder 6-liter Perkins Phaser Euro 2 DI diesel engine. The tests were conducted at 47 kW brake power output at 1500 rpm. The particle size distribution was determined from the engine-out exhaust sample using a Dekati microdilution system and nano-SMPS analyzer. The results showed that for air RSO had higher particle mass than diesel and that this mass decreased as the oxygen level was increased.

The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function temperature. It should be highlighted that methane is a greenhouse gas that similarly to carbon dioxide contributes to global warming and climate change. An oxidation catalyst was used to investigate CO₂, N₂O and CH₄ GHG emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. The results were determined under hot start conditions, but in congested traffic the catalyst cooled below its light-off temperature and this resulted in considerable N₂O emissions as the oxidation catalyst temperature was in the N₂O formation band. This showed higher N₂O during hot start than for diesel fuel and B100 were compared. The B100 fuel was Fatty Acid Methyl Ester (FAME), derived from waste cooking oil, which was mainly RME.

Small diesel engines are a common primer for micro and mini-grid systems, which can supply affordable electricity to rural and remote areas, especially in developing countries. These diesel generators have no exhaust after-treatment system thus exhaust emissions are high. This paper investigates the potential of introducing simulated synthetic gas (syngas) to diesel in a small diesel engine to explore the opportunities of widening fuel choices and reducing emissions using a 5.7kW single cylinder direct injection diesel generator engine. Three different simulated syngas blends (with varying hydrogen content) were prepared to represent the typical syngas compositions produced from downdraft gasification and were injected into the air inlet. In-cylinder pressure, ignition delay, premixed combustion, combustion stability, specific energy consumption (SEC), and gaseous and particle emissions were measured at various power settings and mixing ratios.

The accumulation and release of particulate matter within the exhaust system of a modern light-duty diesel engine was studied during a step cold start to three steady state load conditions, idle, 10 and 15kW. Changes in particulate mass concentration through the various components of the exhaust system were dependent on the previous short-term history of the engine operation, and on the engine speed reached during cold start. Particulate matter was deposited within the oxidation catalyst when cold and in the downstream exhaust silencer at idle and low power conditions. Particulate matter was released from the first silencer at all three test conditions and this release exceeded the deposition in the downstream silencer and resulted in a net exhaust system particulate blowout, at all three test conditions. This was a large fraction of the tailpipe emissions at all three test conditions.

A method of cleaning diesel engine lubricating oil on-line was investigated using a bypass fine particulate filter followed by an infra-red heater to remove water vapour and light diesel fractions in the oil. The impact of this oil recycler on the gaseous and particulate emissions was investigated over a 300 hour oil age period. A Ford 1.8 litre IDI passenger car diesel engine was used with engine out emission sampled every 15-20 hours. The tests were carried out at 2500rpm (52% of the maximum speed) and 12.3 kW with 47 Nm load (43% of the maximum load and 29% of the maximum power). The EGR level at this condition was 15%. A stop start test cycle was used with a cold start each time and a typical test period of 2-3 hours. The results showed that the recycler had its greatest influence on emissions for fresh oil when there was a large reduction in particulate emissions due mainly to large reductions in the ash, carbon and unburned lubricating oil fractions.

Two Ford IDI passenger car diesel engines, 1.6 and 1.8 litres, were tested over a 100 hour lube oil ageing period with engine out emission samples every 15 hours. The 1.6 litre engine was tested with 5% EGR and the 1.8 litre engine with 15% EGR. Comparison was also made with previous work using an older Petter AA1 engine. The three engines had different dependencies of particulate emissions on the lube oil age. The 1.6 litre engine increased the particulates from 1 to 2.5 g/kg of fuel, whereas the 1.8 litre engine first decreased the particulate emissions from 3 to 1 g/kg over 50 hours of oil age and then they increased to 2 g/kg at 100 hours. This was similar to the previous work on the Petter AA1 engine, where the emissions first decreased and then increased as the oil aged. For the 1.8 litre engine the lube oil fraction of the VOF was high with fresh oil and decreased with time for the first 50 hours and then remained steady.

Diesel exhaust particle size distribution and total number concentration were measured at different positions along the exhaust system of a practical light-duty passenger car diesel engine. Continuous particle size measurements during the diesel cold start were made in 12 particle size ranges using the ELPI particle size analyser. Three engine speeds were studied using a step cold start procedure to the set load and speed condition. The exhaust system had an oxidation catalyst with hydrocarbon absorber and two silencers. Particle size distributions were determined upstream and downstream of the catalyst and the two silencers. There were considerable variations in the particle number and size distribution after the cold start. The catalyst was shown to act as a store for fine particles and there were further particle losses across the two silencers.

Hydrogenated Vegetable Oil (HVO) diesel fuels have the potential to provide a reduced carbon footprint for diesel engines and reduce exhaust emissions. Therefore, it is a strong candidate for transport and diesel powered machines including electricity generators and other off-road machines. In this research, a waste cooking oil derived HVO diesel was investigated for its combustion and emission performance including ignition delays, size segregated particulate number emissions and gaseous emissions. The results were compared to the standard petroleum diesel. A EURO5 emission compliant three litre, direct injection, intercooled IVECO diesel engine equipped with EGR was used which has a maximum power output of 96kW. The engine was equipped with an integrated DOC and DPF aftertreatment system. Both the upstream and downstream of the aftertreatment emissions were measured. The tests were conducted at different RPM and loads at steady state conditions.